چکیده انگلیسی

Four experiments examined subjective experience during retrieval in the DRM false memory paradigm [Deese, J. (1959). On the prediction of occurrence of particular verbal intrusions in immediate recall. Journal of Experimental Psychology, 58, 17–22; Roediger, H. L., & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803–814]. Subjects studied lists of related words that were associated with critical non-presented words and then took a recognition test in which they made judgments about their experience of each test item. We tested the prediction from [Whittlesea, B. W. A. (2002). False memory and the discrepancy–attribution hypothesis: The prototype-familiarity illusion. Journal of Experimental Psychology: General, 131, 96–115] discrepancy–attribution hypothesis that subjects experience critical lures as surprising, and that the experience of surprise leads them to call the lures old. We found that subjects were not surprised when they encountered critical lures on a recognition test and, in fact, they reported that they expected to see critical lures more than they expected to see words that they had actually studied. When subjects did experience words as surprising, they called the words new, not old. The results support the idea that false memories in the DRM paradigm occur when critical lures are activated in memory and fluently processed on a test, leading subjects to experience critical lures in much the same way that they experience words they actually studied. The results do not support the idea that false memories are surprising, as stated by the discrepancy–attribution hypothesis.

مقدمه انگلیسی

One remarkable aspect of false memories is the compelling subjective experience that often accompanies them. For example, in Loftus’s misinformation paradigm (Loftus, Miller, & Burns, 1978), when subjects witness an event and then read a narrative that contains misinformation, they falsely remember the misinformation on a later memory test (Roediger, Jacoby, & McDermott, 1996), they attribute the misinformation to the actual event even when told that the narrative contained no true information (Lindsay, 1990), and they are willing to bet money on their false memories (Weingardt, Toland, & Loftus, 1994). In studies of imagination inflation, when subjects repeatedly imagine an event, on a later memory test they will sometimes report that the imagined event actually occurred, even though it did not, and moreover will claim that they consciously remember experiencing the occurrence of the imagined event (Goff & Roediger, 1998). False memories also occur in laboratory tasks with relatively impoverished materials like word lists. When subjects study lists of related words that are associated with a critical non-presented word, they will falsely recall and falsely recognize the critical word at very high levels, and when asked to judge their subjective experience, they claim that they consciously remember experiencing the word when it was presented (Deese, 1959 and Roediger and McDermott, 1995; see Gallo, 2006, for review). All of these examples suggest that subjects often experience false memories in much the same way that they experience true memories, and that the compelling subjective experience associated with memory illusions is partly responsible for leading people to mistakenly label their illusory recollections as memories.
One current theory suggests that two sets of processes are involved in the arousal of false memories: Illusory recollections occur when related concepts are activated in memory (Anderson, 1983 and Collins and Loftus, 1975), and when monitoring processes that guide decisions about what to call a memory fail to distinguish between events that actually occurred in the past and events that did not occur but were activated in memory (Johnson, Hashtroudi, & Lindsay, 1993). This theory is known as the activation/monitoring framework (Roediger et al., 2001 and Roediger et al., 2001), similar in many ways to Johnson et al.’s source monitoring framework. The activation/monitoring framework proposes that when subjects study lists of related words that are associated with a non-presented critical word, activation spreads throughout semantic associative networks from the studied words to the critical word, thereby partially activating the critical word. When memory for the words is assessed, failures in the ability to monitor the source of activation during retrieval lead subjects to make the mistaken claim that non-presented critical words were originally studied.
There is considerable support for the activation/monitoring account of false memories in the DRM paradigm (see Roediger et al., 2001 and Gallo, 2006). For example, backward associative strength, the degree to which list items tend to evoke the critical item in association norms, is the strongest predictor of false recall (Deese, 1959, Gallo and Roediger, 2002 and Roediger et al., 2001). Just as studying semantically related words produces false memories for non-presented semantic associates, studying phonologically related words derived from the same lexical neighborhood (Luce & Pisoni, 1998) also leads to false recall and false recognition of non-presented phonological associates (Sommers and Huff, 2003 and Sommers and Lewis, 1999). Further, lists that contain both phonological and semantic associates produce superadditive effects on false recall (Watson, Balota, & Roediger, 2003). Finally, older adults and other populations with deficits in memory monitoring abilities at retrieval show heightened levels of false recall and false recognition (Balota et al., 1999, McCabe and Smith, 2002 and Norman and Schacter, 1997). This brief review represents only a small portion of the evidence in favor of the activation/monitoring framework (see Gallo, 2006; for a detailed review), although of course other theories of these phenomena have been developed. The evidence suggests that, in the DRM paradigm, the critical non-presented word becomes activated in memory, and on a test, subjects are unable to distinguish well between non-presented critical words and words that they actually studied. The subjective experiences of critical words and list words seem largely isomorphic.
Another theory explaining illusory recollections is Jacoby’s attributional theory (Jacoby, Kelley, & Dywan, 1989), which also holds that subjective experience plays a critical role in guiding people’s decisions about what to call a memory, sometimes leading to false memories. The attributional view of memory proposes that people use a fluency heuristic when deciding whether an event is a memory, attributing the fluency of their current processing to indicate that they had experienced an event previously (Jacoby & Dallas, 1981). However, if processing fluency is enhanced by some other means, it may be mistakenly attributed to prior experience. For example, Jacoby and Whitehouse (1989) primed some words in a recognition memory test by briefly flashing the word immediately before it was shown on the test. Priming the words on the test enhanced the fluency of processing those words, leading to increased false alarm rates to non-studied words. (Rajaram, 1993; also showed that this manipulation enhances “know” judgments, in the procedure in which subjects are asked to judge whether they remember or know that they had studied a word). The effects of processing fluency are also observed in other paradigms. Jacoby, Woloshyn, & Kelley (1989) showed that when subjects were asked to judge whether a name was famous, they were more likely to mistakenly judge a non-famous name to be famous when the name had been repeated from an earlier session, because subjects attributed their fluent processing of the repeated name to indicate that the name was famous. Similarly, Jacoby, Allan, Collins, and Larwill (1988) had subjects judge the loudness of a background noise in which words were presented. When words were repeated from an earlier experience, subjects judged the noise to be less loud, even though the objective noise level was the same. Fluent processing of repeated words led subjects to indicate that the noise level was less loud. Just as the activation/monitoring view holds that individuals experience illusory recollections in much the same way as they experience their true memories, the fluency–attribution view also suggests that processing fluency is responsible for both true and false memories, and illusory memories occur when subjects mistakenly attribute fluent processing to the past. Roediger and McDermott (1995) suggested that fluent processing of the non-studied item associatively related to the list might also be partly responsible for the power of the associative memory illusion. Because the critical (non-studied word) is associated to the studied words, it will be processed quite fluently and may give rise to a false sense of familiarity or even recollection.
Recently, Whittlesea and his colleagues (Whittlesea, 2002 and Whittlesea and Williams, 1998) have put forth an attributional explanation of false memories, based on the discrepancy–attribution hypothesis, as an alternative to spreading activation theories and Jacoby’s fluency theory. According to Whittlesea, Masson, and Hughes (2005), no associative activation needs to be assumed to explain the DRM illusion, and the critical item is not experienced as fluently processed, but instead is experienced as surprising. They stated that:
[The discrepancy–attribution hypothesis] provides an alternative interpretation of the DRM effect, one that does not involve spreading activation. According to this account, subjective experiences such as the feeling of familiarity are produced by an evaluation process that monitors the integrity of ongoing performance. This evaluation takes into account the apparent quality of current processing as well as those aspects of the current stimulus and context that are salient to the person; it leads the person to develop an attitude toward their performance. Of particular relevance to the DRM effect, this process can sometimes cause the person to experience a perception of discrepancy, a feeling of surprise caused by the apparent mismatch between expectations raised by some parts of a processing experience and the actual outcome. This perception motivates the person to seek an explanation, attributing the surprise to some plausible source in covert characteristics of the current stimulus or environment, the person’s current state (mood or disposition), or in the past. When this perception is unconsciously ascribed to a source in the past, the person experiences a conscious feeling of familiarity (p. 421).
The discrepancy–attribution view states that false memories occur when subjects experience a discrepancy between the processing fluency that they expect to experience on a test and the actual fluency of processing that they experience. For example, conceptual factors may lead the subject to expect the critical item (like “sleep” in one of the lists) but the fact that the perceptual form of the item had not been experienced leads to the discrepancy and the conscious feeling of surprise. The critical aspect of the discrepancy–attribution account hinges upon the subjective experience that occurs when individuals have a false memory. Specifically, when a discrepancy occurs between the expected fluency of processing and actual fluency of processing, subjects experience surprise, and this experience of surprise leads them to attribute their surprise to the item being old, thereby producing false memories (see Whittlesea et al., 2005, Whittlesea and Williams, 1998 and Whittlesea and Williams, 2001). As Whittlesea et al. (2005) wrote: “Because they [participants] are unable to understand the cause of variations in their performance, they consciously experience surprise” (p. 422, emphasis is ours).
Whittlesea and his colleagues have provided a range of evidence for the discrepancy–attribution account of false memories. For example, Whittlesea and Williams (1998) had subjects study a list that contained words, orthographically irregular nonwords (e.g., “stofwus”), and orthographically regular nonwords (e.g., “hension”). On a subsequent recognition test that included both types of items as lures, subjects showed the greatest levels of false alarms to the regular nonwords. Whittlesea and Williams argued that orthographic processing of the regular nonwords was fluent, because the regular nonwords followed the orthographic patterns found in English, but semantic processing of those nonwords was nonfluent, because the nonwords were meaningless. Further, they argued that the discrepancy between orthographic processing and semantic processing led subjects to experience surprise, and subjects then attributed their surprise to the item being old (but see Cleary, Morris, & Langley, 2007, for an alternative explanation).
In other experiments, Whittlesea and Williams (2001) had subjects study a list of words and then take a recognition test. Each word on the test occurred at the end of a sentence that either predicted or did not predict the word. For example, when the test word was “broom,” the sentence, “She cleaned the kitchen with a broom” predicted the occurrence of the target word better than the sentence, “She couldn’t find a place to put the broom.” In the latter sentence, many more words could potentially complete the sentence stem besides “broom.” Whittlesea and Williams also manipulated whether or not a 250 ms pause occurred between the end of the sentence stem and before the target word. They found that false alarms to non-studied words were greater when the words occurred in predictive sentences than when they occurred in non-predictive sentences, but only when there was a pause between the sentence stem and the target word. They argued that predictive sentences led subjects to expect to see the target words that fit the sentence. When a non-studied word appeared after a predictive sentence, with a delay between the sentence stem and the target word, processing of the entire sentence was fluent but the processing of the target word itself was relatively nonfluent. Just as in the “hension” experiment, Whittlesea and Williams proposed that this discrepancy in processing fluency led subjects to experience surprise, and subjects attributed their surprise to the word being old.
Whittlesea (2002) has also argued that the experience of surprise is responsible for false memories in the DRM paradigm (see also Whittlesea et al., 2005). For example, Whittlesea (2002) wrote:
The illusion of familiarity for prototypes [the DRM associative memory illusion] is not a direct product of their similarity to the study set. Instead, that feeling comes about through two additional steps. First, the similarity causes enhanced production of some, but only some, aspects of processing the prototypes at test. Second, evaluation of this enhanced production leads to the interpretation that it is discrepant with other aspects of processing that are not enhanced… The perception that aspects of a current experience are discrepant occurs when these aspects fit surprisingly well or surprisingly poorly, for a reason that is not immediately clear (hence the surprise)… According to the discrepancy–attribution hypothesis, people experience a feeling of familiarity when certain aspects of their current processing appear surprising, for indefinite reasons, and the past seems to be a plausible source of influence (pp. 97–98).
Thus, according to the discrepancy–attribution hypothesis, when a non-presented critical word like “sleep” appears on a recognition test, the fluency of conceptual or semantic processing is enhanced relative to the fluency of perceptual processing of the critical word, because words related to the critical word were seen in the study phase (enhancing conceptual processing of the critical word) but the critical word itself was never seen (making perceptual processing of the critical word relatively nonfluent). According to Whittlesea and his colleagues, the discrepancy between conceptual and perceptual fluency when processing the critical words causes a conscious experience of surprise, and the experience of surprise is assumed to be the basis of false memories in the DRM paradigm (see Whittlesea et al., 2005; p. 422). Whittlesea has proposed that the discrepancy–attribution hypothesis provides a superior account of false memories in the DRM paradigm because it does not rely on the concept of spreading activation in an associative network (see Whittlesea, 2002 and Whittlesea et al., 2005).
Whittlesea et al. (2005) argued that if surprise were the basis for false memories in the DRM paradigm, then a procedure that presumably eliminates surprise should also eliminate the illusion. In their Experiment 3, subjects were shown DRM lists and were instructed to generate the non-presented critical word after study. Whittlesea et al. reasoned that generating the critical word would eliminate the surprise of seeing the word on a subsequent recognition test and, therefore, would eliminate the illusion. Indeed, they found that generating the critical word reduced false recognition. Of course, this procedure does not provide any direct measure of surprise, and there are many other possible explanations for the reduction in false memories that occurred after generating the critical word. For example, Libby and Neisser (2001) also had subjects generate critical words after studying DRM lists and also found reductions in false memories. However, those authors made no reference to “surprise” in their analysis, instead attributing the reduction to a shift from a gist-based strategy to a verbatim-based strategy following generation (cf. Brainerd & Reyna, 2002).
We see several problems with the discrepancy–attribution account of false memories in the DRM paradigm. First, no direct evidence has been produced to indicate that subjects experience surprise when they see non-presented critical words on a memory test, even though the surprise is hypothesized to be conscious (Whittlesea et al., 2005; p. 422). This claim is reasonable, because the concept of “unconscious surprise” makes no sense; the experience of surprise is a conscious one, by definition. Second, a variety of evidence suggests that subjects experience false memories of critical words in much the same way that they experience veridical memories of words that they actually studied. The discrepancy–attribution account, on the contrary, holds that the subjective experience of critical words differs from the experience of other words in that critical words are surprising. Third, the idea that non-presented critical words produce surprise seems inconsistent with other literature on the subjective experience of surprise (for a review, see Reisenzein, 2000). For example, research by Meyer and colleagues, among others, typically induces the experience of surprise by establishing a schema or expectation in the minds of subjects and then violating that expectation (e.g., see Meyer et al., 1991, Meyer et al., 1997 and Schutzwohl, 1998). In the DRM paradigm, studying lists of associatively related words also establishes a schema by activating associative networks, but non-presented critical words are consistent with the activated networks, and the critical words are falsely recalled and falsely recognized because they are consistent with the network’s activation pattern. Based on this prior research on the experience of surprise, it seems plausible that critical words are experienced as unsurprising on the test. However, no prior research has assessed the subjective experience of surprise in the DRM paradigm.
In the present experiments, we investigated whether subjects experienced the occurrence of non-presented critical words in the DRM paradigm as surprising by asking them to make judgments of surprise on a recognition test (Experiment 1). We followed this experiment by asking subjects to judge other types of subjective experience that might, under Whittlesea’s theory, be expected to differ for studied words and critical lures, including the expectedness of the words on the test, their unusualness, and their readability (Experiments 2–4). Our goal was to investigate whether subjects experienced studied words and critical lures associated with those words differently, and whether their subjective experience was related to memory performance. The discrepancy–attribution hypothesis suggests that critical lures should be experienced as more surprising than other words on the test, and that this increased surprise should be positively correlated with the likelihood that an item will be judged as “old.” In contrast, the activation/monitoring, source–monitoring, and fluency—attribution accounts suggest that studied words and critical lures are both fluently processed and will be given similar surprise ratings. Further, these frameworks predict that words judged to be surprising (and therefore not fitting the associative network activated by the studied lists and not processed fluently) would be called “new.”
Experiment 1: How surprised are you to see this word?
In Experiment 1, subjects studied lists of associatively related words and took a recognition test. For each word on the recognition test, they were asked, “How surprised are you to see this word on the test?” They made their responses using a 5-point scale (where 1 = very surprised, and 5 = not very surprised). After making the surprise judgment, subjects then judged whether the word was old or new, using a similar 5-point scale to assess confidence in their recognition decision (1 = sure old, and 5 = sure new). According to the discrepancy–attribution account of false recognition, subjects should experience critical words as more surprising than other words on the recognition test, and the subjective experience of surprise should compel them to call the words old. This relationship between the experience of surprise and the decision to call a word old would be reflected by a positive correlation between the surprise judgments and the old/new judgments.